Longevity beats biodegradability

The Redwood Blog

Published: 24 March, 2015

Mike Redwood

I was involved in a webinar on sustainability four weeks ago and I hope a few people watched. I tried to make two points. First that as a science based industry we have a responsibility to properly define what we are talking about and not lapse into the "greenwash" associated with terms such as "organic", "heavy metal" and "toxic". Secondly, I made the point that if we interrogate the definition of sustainability from the Brundtland Report, which is still the one most commonly used, leather is properly sustainable. This is the case as long as we make it properly, take responsibility for our tannery wastes and treat workers correctly, including providing proper work wear etc.

We are all now packing our bags and heading for APLF in Hong Kong and I see that sustainability is still on the agenda there. I hope that proper attention will be paid to using all terms accurately.

Biodegradability is just such a term. We know that chromium tanned leather does not easily biodegrade and vegetable tanned leathers can exist for many centuries in most conditions. In general a substance, component, or product is called biodegradable if it can be converted by living organisms into its basic components (for example into carbon dioxide and water). In the EU a substance is considered to be ‘Readily Biodegradable’ if more than 70% of the substance is converted within 28 days. The definition supported in the EU regulation is ‘the extent to which degradation into carbon dioxide (CO2), water and minerals takes place’.

The paragraph above I wrote in a paper published in 2013 in the JSLTC, which every leather chemist should subscribe to. So ignorance is no excuse. The underlying point is that leather wins on longevity rather than biodegradability.

Leather is wonderful because it lasts a long time. This means articles made from it can usually be repaired and many last for generations. The Coach brief case I will carry my papers to APLF in was bought in 1987 and has worn really well. I expect my grandchildren to be using it. It has not yet needed repairing at all. My two pairs of Church's shoes have both been resoled a few times and still polish up very well.

So when we think about leather consider first longevity, then consider end of life. If a leather seat is really finished then more often than not the leather can be taken and made into smaller articles, which is what some U.S. Airlines did last year. In other instances leather can be ground up and used for areas like insoles or other materials. (As long as we define them correctly and do not call them leather).

To make leather efficiently biodegradable via reversible tannages and the like will involve some new developments but dropping leather items into landfill to biodegrade is one of the last things we should plan for. Leather is better than that.